The present invention relates to an image processing apparatus that makes image data subjected to image processing. On existing operating systems, the sRGB color space or the standard color space for monitors is used to represent RGB data. When generally used JPEG data is open on a personal computer, for example, the JPEG data is immediately converted into RGB data. The conversion of the JPEG data into the RGB data may give color values outside the color range in the sRGB color space. These color values are not displayable in the sRGB color space and are thus clipped (cut off).
The prior art technique accordingly causes part of the color values in the original JPEG image data to be lost in the course of image processing. The processed image data is kept without restoration of the lost color values. This undesirably leads to deterioration of the JPEG data.